Ball mill



United States Patent Jacob Kurtz Teaneck, NJ.

Dec. 10, 1968 Dec. 22, 1970 Kulite Tungsten Corporation Ridgelield, NJ.

a corporation of New Jersey [72] lnventor App]. No. Filed PatentedAssignee BALL MILL 10 Claims, 4 Drawing Figs.

US. Cl.

241/171, 241/ 176 Int. Cl. B02c 17/10 Field of Search 241/ 171,

[56] References Cited UNITED STATES PATENTS 3,011,727 12/1961 Varkony241/176X 3,212,722 10/1965 Maeder et a1 241/171 Primary Examiner-TravisS. McGehee Attorney-Edward T. Connors ABSTRACT: A motor operated ballmill is provided with opposed receptacles positioned over outlets sothat the receptacles receive milled material, a grating being providedbetween the mill and the receptacle retaining the balls in the mill. Aflap valve is provided for the receptacles to prevent the milledmaterial from reentering the mill.

BALL MILL The present invention relates to a ball mill particularlysuitable for milling dry materials, in which means are providedretaining the balls within the mill while the milled material is allowedto pass to one or more receptacles from which it may be easily removed.

In prior ball mill operations both the grinding media or balls and thefinely ground material were discharged into suitable containers and thenseparated by shaking or sieving the mixture through suitable grates. Inother prior constructions. the ball mills were built with permanenthousings extending practically completely around the walls of thecylinders. The housings carried means for the ball mills to revolve,generally in the form of rings which were provided with suitable gasketmaterials for seals to prevent the leakage of the milled material outwardly of the housing. The milled material fell to the bottom of thehousings and was thereafter removed as by shoveling into receivingcontainers. These constructions were disadvantageous in that in somecases the milled material stuck to the inside walls of the housings andto the outside walls of the ball mills which prevented complete recoveryof the milled material. This was objectionable, not only because of theloss of the material, but also because of the possibility ofcontamination of another material thereafter placed in the mill.

The present invention aims to overcome the difficulties anddisadvantages of prior ball mills by providing an improved ball millwhich automatically separates. the balls from the ground materialretaining the balls within the mill and discharging the ground material.

In accordance with the invention this is accomplished by providing aball mill in which the cylinder has its outlet in fluid communicationwith a receptacle, blocking means being provided between the cylinderand the receptacle so that the balls are retained in the, mill. Thereceptacle is provided with an outlet for the rapid discharge of theaccumulated ground material. Another feature is the provision of flowblocking means preventing the passage of the milled material back intothe cylinder from the receptacle after it has been discharge therein.

The construction is advantageous in that it may be readily incorporatedinto'existing ball mills with a minimum of conversion expense.

Other objects and advantages of the invention will be apparent from thefollowing description and from the accompanying drawing which shows, byway of example, an embodiment of the invention.

In the drawing:

FIG. 1 is a schematic diagram showing a ball mill in accordance with theinvention. 1

FIG. 2 is a side view of a grating used in the ball mill.

FIG. 3 is a plan view of the grating shown in FIG. 2.

FIG. 4 is a sectional view of a receptacle attached over the outlet ofthe ball mill in accordance with the invention.

Referring to the drawing there is shown in FIG. 1 a ball mill lincluding a pair of supporting frame members 11 and 12. The ball millincludes a cylinder 14 having ends 15 and 16. A

plurality of mounting members 17 and extend through the walls of thecylinder 14 and are used to attach longitudinally extending barspositioned on the inner surface of the cylinder 14 (not shown).Preferably a pair of receptacles l9 and 20 are attached to the cylinder14, the receptacles being oppositely positioned so as to balance theassembly. The receptacles l9 and 20 are identical. At end 16 of the ballmill 10 is a ring gear 21 engaged by a pinion 22 rotated by a motor 24through a gear reduction box 25. The motor and gear box assembly may becarried on a shelf 26 of the frame 12.

Positioned between the receptacles 19 and 20 and the cylinder 14 are thegratings 30 each having a pair of mounting lugs 31 and 32 and agenerally 'rectangularly shaped frame 34. Spaced somewhat away from theframe 34 is an inner frame 35 carrying a plurality of rods 36, thespacing between the rods 36 and between the frames 34 and 35 being lessthan the diameter of the balls used so that the grating 30 effectivelyseparates the milled material from the balls. The upper frame 35 isattached to the lower frame 34 by members 37 and 39. The grating memberis positioned in the outlet of the cylinder 14 with the upper framefacing the interior of the cylinder. The receptacles 19 and 20 aresecured in position over the grating holding it in position.

A sectional view of the receptacle 19 is shown in FIG. 4. A tubularmember 40 is provided with a flanged end 41 adapted to be secured overthe grating 30 about the outlet of the cylinder 14, suitable apertures42 being provided for the passage of retaining bolts. The tubular member40 extends through an opening in the sidewall 43 of the receptacle 19,the sidewall 43 being preferably of generally cylindrical shape.

The receptacle 19 may be secured in position with the tubular member 40by welding 44 or other suitable means. The inner end of the tubularmember 40 is made at an angle providing a short side 45 and a longerside 46. A flap valve 48 is pivotably attached to the short side 45 by ahinge 49. The cylindrical wall 43 is closed by an end wall 50 at one endthereof while the other end is provided with a throat 51 having anoutlet opening 52 at its outer end. About the outlet opening 52 ispositioned a ring 54 apertured to receive a swing bolt 55 and at itsopposite end fitted with a shoulder bolt 56. A disclike closure member57 is pivoted in. the swing bolt 55 and notched so as to be releasablysecured by the shoulder bolt 56.

Referring to FIG. 1 it will be noted that two receptacles 19 and 20 arepositioned on opposite sides of the cylinder 14 after the ball millingcycle has been completed, the ball mill having been rotated with solidclosures in place blocking the openings adapted to receive thereceptacles l9 and 20 until the desired fineness of the milled materialis achieved. Obviously a single receptacle might be .used if suitablecounterbalance means is provided.

The cylinder 14 may be about half filled with balls or with balls andmaterial being milled. As the cylinder rotates the finer of the milledmaterial passes through the grating 30 into the tubular member 40 fromwhere it drops into the receptacle 19 when the flap valve 48 opens. Asthe cylinder 14 continues to rotate the flap valve is closed by gravityretaining the finely milled material in the receptacle 19. The millingoperation may be stopped and the machine turned so that one of thereceptacles 19 is positioned at the lower end thereof whereupon theshoulder bolt 56 may be loosened and the disc closure member 57 swungaway allowing the milled material to be removed.

It will be noted that the flap valve 48 will be open so as to receivematerial from the ball mill during about one half of each revolution andclosed during the remaining half of the revolution so as to prevent thematerial from falling back into the ball mill.

While the invention has been described and illustrated with reference toa specific embodiment thereof, it will be understood that otherembodiments may be resorted to without departing from the invention.Therefore, the form of the invention set out above should be consideredas illustrative and not as limiting the scope of the following claims.

Iclaim:

1. A ball mill comprising a rotatable cylinder, means to rotate thecylinder, outlet means for the cylinder, a plurality of balls within thecylinder, means blocking the passage of balls outwardly through saidoutlet but allowing the passage of material below a predeterminedblocking a receptacle secured to said cylinder about said outlet, flowblocking means preventing flow of material back from said receptacle tosaid cylinder, and discharge outlet means for the said receptacle.

2. A ball mill according to claim 1 in which a pair of receptacles areprovided oppositely positioned on said cylinder.

3. A ball mill according to claim 1 in which said means blocking thepassage of balls outwardly through said outlet but allowing the passageof material below a predetermined size is a grating including aplurality of rods spaced a predetermined distance.

4. A ball mill according to claim 1 in which said receptacle is ofcylindrical shape having its axis positioned tangentially to theperiphery of said cylinder.

5. A ball mill according to claim 4 in which an outlet is positioned atone end of said receptacle.

6. A ball mill according to claim 5 in which a plate is swingablymounted in closing relationship with the outlet of said receptacle.

7. A ball mill according to claim 1 in which said flow blocking means isa gravity actuated flap valve positioned at the inlet to said receptaclesuch that it falls open to receive material during a portion of therevolution of the cylinder and falls closed during the remainder of therevolution of the cylinder so that material does not pass back from thereceptacle to the cylinder.

8. A ball mill according to claim 7 in which a flanged tube is providedbetween said receptacle and said cylinder, the flanged end of the tubeattached to said cylinder about the cylinder outlet, the other end ofsaid tube extending within said receptacle, said flap valve pivotablymounted on said other end of said tube.

9. A ball mill according to claim 3 in which said receptacle is ofcylindrical shape having its axis positioned tangentially to theperiphery of said cylinder, outlet means positioned at one end of saidreceptacle, a plate swingably mounted in closing relationship with theoutlet of said receptacle, said flow blocking means being a gravityactuated flap valve positioned at the inlet to said receptacle so thatit falls open to receive material during a portion of the revolution ofthe cylinder and falls closed during the remainder of the revolution ofthe cylinder in order that material does not pass back from thereceptacle to the cylinder, and a flange tube is provided between saidreceptacle and said cylinder, the flanged end of the tube attached tosaid cylinder about the cylinder outlet, the other end of said tubeextending within said receptacle, said flap valve being pivotablymounted on said other end of said tube.

10. A ball mill according to claim 9 in which a pair receptacles areprovided oppositely positioned on said cylinder.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 549094 Dated December 22. 1970 Inventofls) Jacob Kurtz It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 40, change "discharge" to --discharged-.

Column 1, line 59, remove the word "and" after "17''.

Column 2, Claim 1, line 65, after "predetermined" remove the word"blocking" and insert the word --size,--.

Column 4, Claim 10, line 18, after "pair" insert the word --of-- Signedand sealed this 23rd day of March 1971 (SEAL) Attest:

WILLIAM E. SCHUYIER, JR.

EDWARD M.FLETCHER,JR.

Commissioner of Patents Attesting Officer

